Abstract: A method of measuring the state of flow above an airfoil using an estimation of the velocity field based on a combination of Particle Image Velocimetry PIV and multiple surface pressure measurements processed through a POD/mLSE algorithm. Integral to the POD/mLSE algorithm is the estimation of the global POD coefficients. The utility of these time dependent coefficients, which are estimated from surface pressure only, are demonstrated in a simple proportional feedback loop (as the time series to drive the actuators) to keep the flow attached. This method requires realistic feedback flow control since surface measurements and not inflow measurements are required for practical applications. The estimation method works well with dynamic strain on flexible bodies and is not limited to estimation from pressure only.

Abstract: A ventilation system with hardware to direct two independent airflows, wherein an outer airflow (at least partially) surrounds the an inner airflow. Preferably the inner and outer airflows come from different sources such that the air of the inner airflow has higher associated costs than the air of the outer airflow. For example, the inner airflow may be more cleaned and/or more thermally conditioned than the outer airflow. The inner airflow may have a different velocity than the outer airflow.

Abstract: A method of measuring the state of flow above an airfoil using an estimation of the velocity field based on a combination of Particle Image Velocimetry PIV and multiple surface pressure measurements processed through a POD/mLSE algorithm. Integral to the POD/mLSE algorithm is the estimation of the global POD coefficients. The utility of these time dependent coefficients, which are estimated from surface pressure only, are demonstrated in a simple proportional feedback loop (as the time series to drive the actuators) to keep the flow attached. This method requires realistic feedback flow control since surface measurements and not inflow measurements are required for practical applications. The estimation method works well with dynamic strain on flexible bodies and is not limited to estimation from pressure only.